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Biomedical subjects

M M Meguid

Publications and source records attributed to M M Meguid.

At least 145 records · Page 8Linked to original sources
PubMed1988

Complications of abdominal operations for malignant disease.

The incidence of morbidity and mortality in 365 consecutive patients with a mean age of 60 years who underwent intraabdominal operation for a variety of cancers involving different organ systems over a recent 2-year period was analyzed. The primary tumor sites were the esophagus (21 patients), gastroduodenum (33 patients), liver and gallbladder (6 patients), pancreas (15 patients), colorectum (101 patients), lymphoproliferative disorders (35 patients), abdominal carcinomatosis (45 patients), genitourinary and gynecologic systems (94 patients), and other sites (15 patients). One hundred eighty-two patients (49 percent) had 1 or more complications (grouped as gastrointestinal, septic, cardiopulmonary, and nonseptic) and 47 patients died (12.9 percent). The 145 patients who underwent a palliative procedure had the highest morbidity and mortality rates (41 percent and 21 percent, respectively). In the 168 patients who had curative resection, the morbidity and mortality rates were 39 percent and 9 percent, respectively, and in 51 patients with a diagnostic laparotomy, 20 percent and 4 percent, respectively. Age was not a contributory factor. The 177 malnourished patients had a significantly higher incidence of complications (72 percent) and postoperative death (23 percent) than the well-nourished patients (29 percent and 4 percent, respectively; p less than 0.001). These differences also existed with each form of complication. Of those patients without complications, the majority resumed consuming 60 percent of their caloric requirements by postoperative day 9. In the majority of patients with complications, resumption of adequate oral intake occurred by postoperative day 20.

Abdominal Neoplasms↗
PubMed1988

Indomethacin decreases carrageenan-induced peritoneal adhesions.

For evaluation of a rat intra-abdominal adhesion model, 48 study rats were each given an intraperitoneal injection of 1 ml of 1.5% carrageenan solution and 48 control rats were each given 1 ml of sterile saline solution. Thereafter, 6 control and 6 study rats were killed on days 2, 3, 4, 5, 7, 9, 14, and 21 for assessment of the temporal nature of adhesion formation. No peritoneal reaction or adhesions occurred from saline solution. Carrageenan induced a generalized peritonitis between days 2 and 7. The frequency of adhesions from day 5 onward was 66%. The effects of celiotomy and of systemic indomethacin on carrageenan-induced adhesion formation were then examined. Rats underwent a standardized celiotomy and, on closure of the abdomen, received either an intraperitoneal injection of saline solution (n = 72) or an intraperitoneal injection of carrageenan solution (n = 96). Both groups were then randomized to receive either no indomethacin (IND-0), a single preoperative dose of indomethacin (IND-1), or four perioperative doses of indomethacin (IND-4). Then, 2, 5, 14, and 21 days later, rats from each group were killed, the extent of intraperitoneal adhesions was assessed, and the nature of any adhesions was histologically examined. Celiotomy plus intraperitoneal saline solution produced no adhesions. Celiotomy plus intraperitoneal carrageenan solution (IND-0) significantly increased adhesions to 83%. Preoperatively and perioperatively administered indomethacin significantly decreased the adhesion formation rate to 49%.

Abdomen↗
PubMed1987

Observations on predicted brain influx rates of neurotransmitter precursors. Effects of tumor, operative stress with tumor removal, and postoperative TPN of varying amino acid compositions.

Effects of tumor, operative stress and tumor removal, and postoperative TPN of varying amino acid compositions on brain levels of tryptophan or tyrosine as predicted by their brain influx rates were studied in normals and in malnourished cancer patients. Concentrations of the large neutral amino acids (LNAA) were determined in patients before and after tumor removal, and in postoperative patients before and after receiving either a standard TPN solution (STD-TPN), or a branched-chain amino acid solution (BCAA-TPN). The LNAA were altered in all groups versus normals. Brain influx rates showed the following: in preoperative patients, predicted brain tryptophan levels were below normal (P less than 0.001), whereas tyrosine levels were within or above normal; no significant differences between pre- and postoperative tryptophan or tyrosine levels; postoperative STD-TPN did not change predicted brain tryptophan concentration from preinfusion values, but BCAA-TPN decreased it (P less than 0.001), underscoring the common transport carrier; and preinfusion predicted brain tyrosine levels were decreased (P less than 0.001) by both types of TPN solutions. These results imply low substrate levels for brain serotonin and catecholamine synthesis, possibly affecting functions dependent on their control.

Amino Acids↗
PubMed1987

Use of serum CPK-MM to monitor response to nutritional intervention in catabolic surgical patients.

Nutritional status of surgical patients is widely assessed using anthropometrics, visceral proteins, and urinary nitrogen losses. Since assay of muscle-specific marker 3-methylhistidine (3MH) is currently limited to research laboratories, routine use of serum creatinine phosphokinase (CPK) and myoglobin is potentially useful in monitoring nutritional repletion of stressed patients. An acute and a temporal phase human studies were done to test this hypothesis. After an overnight fast, nondiabetic, noncardiac patients were given an IVGTT (0.5 g/kg) 3 days after a standard abdominal midline operation. Glucose, insulin, total CPK, myoglobin, and 3-methylhistidine were measured serially. Baseline CPK was elevated threefold above normal range of upper limits, whereas myoglobin was at the upper limit of normality. After the IVGTT insulin rose, (P less than 0.005) and CPK and 3MH fell (P less than 0.005) whereas myoglobin rose and remained elevated throughout the study (P less than 0.05). As long as insulin levels remained elevated, CPK remained depressed. With sufficient TPN to induce positive nitrogen balance (35 kcal and 0.2 g N/kg/day), elevated CPK levels fell and remained depressed in direct correlation with elevated insulin. Greater than 95% of total serum CPK consisted of the isoenzyme CPK-MM. These initial studies indicate that total serum CPK is useful in monitoring the short-term responses of postoperative catabolic patients who receive nutritional repletion.

Adult↗
PubMed1987

A prospective randomized study of the optimal source of nonprotein calories in total parenteral nutrition.

We previously showed that providing 30% of nonprotein calories as lipid eliminated glucose intolerance and ameliorated the other troublesome metabolic complications of total parenteral nutrition (TPN): hepatic abnormalities and hypertriglyceridemia. Whether such a mixed-fuel system is as effective as a hypertonic glucose-only TPN fuel system in achieving an anabolic state was tested in 88 consenting patients randomized to either conventional TPN (25% dextrose and 4.25% amino acids) or modified TPN (15% dextrose, fat, and 5% amino acids). Treatment groups were: group A, no surgery, TPN only; group B, postoperative TPN starting 48 hours after surgery; and group C, preoperative TPN, surgery on day 7 and with continued postoperative TPN. In all groups TPN was given for 14 days while patients were given nothing by mouth. Changes in the indexes of body protein metabolism, reflected by nitrogen balance, serum albumin, blood urea nitrogen, and weight, were measured on days 1 and 14. Nitrogen balance improved in patients randomized to either regimen, but there was no significant difference in the degree of improvement. Albumin levels were maintained, and differences between initial and final values were not significant. Blood urea nitrogen increased in all groups (p less than 0.05); however there was no significant difference between regimens. Patients maintained their weight, and fluid balance data indicated no water retention. Observed weight changes were not statistically significant. In each treatment group an anabolic state occurred and gains in measured protein indexes were similar. Isocaloric replacement of 30% of TPN glucose calories with fat was as effective as glucose-only TPN in achieving an anabolic state without the metabolic complications associated with glucose-only TPN.

Blood Urea Nitrogen↗
PubMed1987

The benefits of Isolator cultures in the management of suspected catheter sepsis.

Until recently, when a patient receiving total parenteral nutrition (TPN) was suspected of having catheter-related sepsis, the catheter was removed and the tip and the patient's blood was cultured. Using this method at our institution, greater than two thirds of the central venous catheters (CVC) removed were sterile, or if colonized, proved not to be the source of sepsis. This practice led to the unwarranted removal of numerous catheters and posed a clinical dilemma because it necessitated replacement of the catheter with its attendant risks, cost, and inconvenience. To address this problem, we instituted a protocol for determining in situ catheter-related sepsis based on a quantitative blood culture method using lysis centrifugation (Isolator; Dupont Co., Wilmington, Del.). When catheter-related sepsis was clinically suspected, quantitative blood cultures were obtained simultaneously via a peripheral (PER) vein and through the CVC suspected as the source of sepsis. The CVC, however, remained in situ pending culture results (approximately 16 to 24 hours). A CVC colony of greater than or equal to five times the PER colony count was considered significant and the catheter was removed. Equivocal colony counts between the CVC and PER cultures were interpreted as incriminating a source of sepsis other than the CVC. An 8-month prospective study was undertaken to evaluate the efficacy of this method for determining in situ catheter sepsis. One hundred third-eight patients received TPN by means of 160 catheters. In 113 patients no sepsis-related problems were noted. In the remaining 25 patients, 28 catheters were suspected as the source of sepsis. Twenty-six catheters were evaluated by the Isolator culture method. In eight instances significant differences in colony counts between the CVC and PER cultures were seen, implicating the CVC as the source of infection. In all these cases the CVC was removed and the patients underwent defervescence. In 18 cases, the CVC samples revealed either no growth or insignificant differences between the CVC and PER colony counts. Nine of these CVCs were removed without clinical improvement. The remaining nine catheters were left in place, and another source of sepsis was ultimately identified and treated. These results confirm the use of the quantitative blood culture method for determining in situ catheter-related sepsis. In all cases, when the catheter was incriminated by culture data, removal of the CVC led to patient improvement.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1986

Postulated cancer prevention diets. A guide to food selections.

We believe that sufficient circumstantial and epidemiologic data exist linking diets and nutrients to cancer to warrant modification of eating habits. The proposed menus and diets are examples of the types of foods that might be beneficial in reducing the risk factors of cancer and also consistent with good nutritional habits.

Diet↗
PubMed1986

Cancer and protein metabolism.

We have reviewed the data that indicate that protein depletion is an important problem in cancer patients. An incomplete, yet useful, idea of the underlying mechanisms emerges. Further, we have seen that the provision of nutritional support may have a beneficial effect on patients with cancer, and we have explored areas of recent advances in nutritional formulation as regards energy and nitrogen source. Finally, data regarding micronutrients affecting nitrogen metabolism were reviewed. The extent to which tumor metabolism and changes secondary to the tumor-bearing state are influenced by micronutrients is not known. Traditional regimens based on the requirements of normal subjects or noncancer patients may not be relevant to the metabolic needs of the cancer patient. This could explain in part the failure of nutritional intervention trials to demonstrate a consistent benefit of nutritional support to the cancer patient. Further information regarding micronutrient needs in normal humans and cancer-bearing patients and their utilization by malignant tumors will have to be obtained.

Animals↗
PubMed1986

Assessment of nutritional status in the oncologic patient.

The term malnutrition is a continuum that progresses from only a disequilibrium of intake in relation to needs, to gross structural and functional changes. Furthermore, these changes may be mutually exclusive. How then do we define malnutrition? Strictly, malnutrition starts, as we have shown, when the patient fails to eat enough to meet needs and progresses through a series of functional changes that precede any changes in body composition. These functional changes are related to the duration of reduced intake and its severity. Finally, body wasting occurs, and biochemical indices become abnormal. To base the definition of malnutrition on any one of these changes is inappropriate. Thus, a patient's nutritional status should be defined by the following criteria: nutrient intake in relation to needs; associated changes in organ function; associated changes in body composition; and associated changes in biochemistry. Only by recognizing the different facets of malnutrition can we define its various manifestations in relation to our clinical objectives. In attempting to achieve this goal, we have found muscle function tests a most useful and objective investigational tool.

Anthropometry↗
PubMed1986

Influence of nutritional status on the resumption of adequate food intake in patients recovering from colorectal cancer operations.

The influence of nutritional status on the resumption of adequate food intake in 101 patients recovering from colorectal cancer operation was examined. Two thirds of these patients were well-nourished; the others were malnourished. Malnutrition criteria were serum albumin of less than 3.5 gm per dl plus any two of the following four factors: recent weight loss greater than 10 per cent or weight for height, mid-arm circumference, and triceps skinfold thickness lower than the tenth percentile. Over half of the well-nourished patients were eating 60 per cent or greater of their caloric requirements by the tenth postoperative day, whereas only one quarter of the malnourished patients had attained this intake. the morbidity and mortality in 33 malnourished patients was 52 and 12 per cent, respectively, compared with 31 and 6 per cent (p less than 0.01) in 68 nourished patients. The duration of postoperative functional starvation in malnourished patients without complications increased to an average of 22 days following a complication and was further prolonged after a complication. Age or operative procedure (curative or palliative) did not influence complication rate. Our data suggest that postoperative nutritional support as either TPN or enteral feeding using an elemental diet is indicated in malnourished patients and in well-nourished patients immediately following a complication requiring therapeutic intervention.

Adult↗
PubMed1986

Leucine kinetics at graded leucine intakes in young men.

A study was carried out with 12 young men to examine the relationships between the intake of leucine and indices of leucine kinetics, using L-[1-13C]leucine as a tracer. Six subjects received L-amino acid diets during 7-day periods supplying leucine in the range of 79 to 20 mg.kg-1.day-1 (Group I) and another six subjects (Group II) received leucine intakes ranging from 20 to 4 mg.kg-1.day-1. Estimations were made of leucine kinetics, at the end of each diet period, when subjects were receiving small isonitrogenous, isocaloric meals during the isotope infusion period. Leucine flux declined with reduced leucine intake and leucine oxidation tended not to change at intakes below 20 mg.kg-1.day-1 (slope not statistically different than zero). Plasma valine increased markedly with further restriction in leucine intake below this level. The daily mass balance of leucine, estimated from the difference between intake and oxidation, became negative at an intake of about 20 mg.kg-1.day-1. These findings are discussed in relation to the published mean and upper range of requirement for leucine in healthy adults, currently taken to be 11 mg.kg-1.day-1 and 14 mg.kg-1.day-1, respectively.

Adolescent↗
PubMed1986

Valine kinetics at graded valine intakes in young men.

Twelve young men, six subjects in each group studied in two phases, participated in an experiment to explore the relationships between valine intake, plasma valine concentrations, and valine kinetics, using 1-[13C]valine as a tracer. Below a valine intake of about 20 mg.kg-1.day-1 plasma valine concentrations reached a low and relatively constant level. The rate of valine oxidation fell with the decline in the intake of amino acid. Below valine intakes of 16 mg.kg-1.day-1, the mean daily rate of oxidation was estimated to be generally higher than the intake level, implying a negative valine balance during the 24 h day. These findings indicate that an intake of 10 mg valine kg-1.day-1 would not be adequate to maintain protein nutritional status. Our results are discussed in relation to the currently accepted 1973 FAO/WHO value of 10 mg.kg-1.day-1 as being the upper range of the valine requirement in healthy adult humans.

Adolescent↗
PubMed1986

Use of 20% fat emulsion in total parenteral nutrition.

Sixteen elderly postoperative patients were randomized in a crossover study comparing isocaloric volumes of 20% and 10% fat emulsions used for total parenteral nutrition (TPN). The caloric intake was maintained constant during the two 7-day periods of each infusion. The indices measured after each period were total volume of fluid administered, change in body weight, hematocrit, serum sodium, creatinine, albumin, blood urea nitrogen, glucose, inorganic phosphate, and cholesterol. The total volume of 10% isocaloric nutrient solution was significantly (p less than .05) greater than that of the 20% solution. A rise in body weight and a fall in serum indices of hydration status were observed; five patients developed clinical signs of overhydration while on the 10% solution. These changes did not occur with the 20% solution. Thus, isocaloric substitution of a 20% fat emulsion for a 10% fat emulsion with TPN prevented overhydration and hemodilution without compromising nutrient intake.

Aged↗
PubMed1985

Aspects of amino acid and protein metabolism in cancer-bearing states.

Overt malnutrition is seen in about 40% of patients hospitalized for treatment of cancer. In patients whose primary treatment modality is surgical, morbidity and mortality is twice as high in the malnourished group as in the normally nourished patients. This clinically important malnutrition is a consequence of obligatory parasitism by the tumor, which grows at its own genetically determined rate and which competes effectively with the host for the limited available nutrients. Administration of extra nutritional support as total parenteral nutrition (TPN) can alter the tumor-host nutritional balance so that host repletion may occur. Provision of a significant proportion of TPN calories as fat diminishes the incidence of glucose intolerance and reduces the incidence of abnormal liver function. In vitro and in vivo studies both show that leucine is the significant controlling branched-chain amino acid in the TPN mixture, and adequate leucine content is a crucial component of effective TPN. Variations in TPN content of large neutral amino acids have important effects on brain tyrosine and tryptophan availability and hence may also effect neurotransmitter activity. Although the usefulness of TPN for correcting malnutrition in cancer patients is clear, the optimal choices of constituents for the TPN mixture continue to evolve.

Adenosine Triphosphate↗
PubMed1985

Preoperative identification of the surgical cancer patient in need of postoperative supportive total parenteral nutrition.

In the absence of specific therapy, nutrition was the mainstay of medicine in ancient times. Because of the current emphasis on modern treatment modalities in the fight against cancer, the provision of adequate nutrition is frequently overlooked. Because of the inconsistent results obtained from randomized trials of total parenteral nutrition (TPN) in cancer patients undergoing chemotherapy and radiation therapy, ambivalence about the usefulness of TPN as an adjunct to cancer therapy (particularly as it pertains to surgical patients) is further confused by the lack of appropriate criteria for the use of TPN postoperatively. The incidence of malnutrition in relation to certain cancer types is high. Malnutrition is associated with a higher incidence of both postoperative complications and mortality when compared to the well nourished patient. Consequently, preoperative criteria were developed to identify that group of cancer patients requiring abdominal operation who are at high risk and in whom planned nutritional support should be initiated postoperatively. Use of these criteria provides a rational basis for the use of TPN postoperatively.

Adult↗